The invention relates to multimedia signal processing, and in particular relates to encoding information into and decoding information from video objects.
xe2x80x9cSteganographyxe2x80x9d refers to methods of hiding auxiliary information in other information. Audio and video watermarking are examples of steganography. Digital watermarking is a process for modifying media content to embed a machine-readable code into the data content. A media signal, such as an image or audio signal, is modified such that the embedded code is imperceptible or nearly imperceptible to the user, yet may be detected through an automated detection process. Most commonly, digital watermarking is applied to media such as images, audio signals, and video signals. However, it may also be applied to other types of data, including documents (e.g., through line, word or character shifting), software, multi-dimensional graphics models, and surface textures of objects.
Digital watermarking systems have two primary components: an embedding component that embeds the watermark in the media content, and a reading component that detects and reads the embedded watermark. The embedding component embeds a watermark by altering data samples of the media content. The reading component analyzes content to detect whether a watermark is present. In applications where the watermark encodes information, the reader extracts this information from the detected watermark.
The invention provides methods and systems for associating video objects in a video sequence with object specific actions or information using auxiliary information embedded in video frames or audio tracks. A video object refers to a spatial and temporal portion of a video signal that depicts a recognizable object, such as a character, prop, graphic, etc. Each frame of a video signal may have one or more video objects. The auxiliary information is embedded in video or audio signals using xe2x80x9csteganographicxe2x80x9d methods, such as digital watermarks. By encoding object specific information into video or an accompanying audio track, the watermarks transform video objects into xe2x80x9cwatermark enabledxe2x80x9d video objects that provide information, actions or links to additional information or actions during playback of a video or audio-visual program. A similar concept may be applied to audio objects, i.e. portions of audio that are attributable to a particular speaker, character, instrument, artist, etc.
One aspect of the invention is a method for encoding substantially imperceptible auxiliary information about a video object into a video signal that includes at least one video object. The method steganographically encodes object specific information about the video object into the video signal. Some examples of this information include identifiers and screen locations of corresponding video objects. The method associates the object specific information with an action. This action is performed automatically or in response to user selection of the video object through a user interface while the video signal is playing.
Another aspect of the invention is a method for encoding substantially imperceptible auxiliary information into physical objects so that the information survives the video capture process and links the video to an action. This method steganographically encodes auxiliary information in a physical object in a manner that enables the auxiliary information to be decoded from a video signal captured of the physical object. One example is to place a watermarked image on the surface of the object. The method associates the auxiliary information with an action so that the video signal captured of the physical object is linked to the action. One example of an action is retrieving and displaying information about the object. For example, the watermark may act as a dynamic link to a web site that provides information about the object.
Another aspect of the invention is a method for using a watermark that has been encoded into a video signal or in an audio track accompanying the video signal. The watermark conveys information about a video object in the video signal. The method decodes the information from the watermark, receives a user selection of the video object, and executes an action associated with the information about the video object. One example of an action is to retrieve a web site associated with the video object via the watermark. The watermark may include a direct (e.g., URL or network address) or indirect link (e.g., object identifier) to the web site. In the latter case, the object identifier may be used to look up a corresponding action, such as issuing a request to a web server at a desired URL. Object information returned to the user (e.g., web page) may be rendered and superimposed on the same display as the one displaying the video signal, or a separate user interface.
Another aspect of the invention is a system for creating watermark enabled video objects. The system includes an encoder for encoding a watermark in a video sequence or accompanying audio track corresponding to a video object or objects in the video sequence. It also includes a database system for associating the watermark with an action or information such that the watermark operable to link the video object or objects to a related action or information during playback of the video sequence.
Another aspect of the invention is a system for processing a watermark enabled video object in a video signal. The system comprises a watermark decoder and rendering system. The watermark decoder decodes a watermark carrying object specific information from the video signal and linking object specific information to an action or information. The rendering system renders the action or information.
Another aspect of the invention is a method for encoding substantially imperceptible auxiliary information into an audio track of a video signal including at least one video object. This method steganographically encodes object specific information about the video object into the audio track. It also associates the object specific information with an action, where the action is performed in response to user selection of the video object through a user interface while the video signal is playing. Alternatively, the action can be performed automatically as the video is played.
Further features will become apparent with reference to the following detailed description and accompanying drawings.